No, it is like a weapon and is only for PC.
Yes, Team Fortress 2 is for Xbox 360 but it doesn't get updated.
I'm doubtful as they mainly just bundled it with HL2 but no-one knows for sure.
Most likely never. Valve only updates the PC (and Mac) version of the game.
No I do not suggest you buy it because, it doesn't update the way the free PC version does and your stuck with the default weapons and maps
Yes Team Fortress 2 is available in the Xbox Arcade Store.
No, there probably wont be because it is easier to add upgrades onto pc rather than xbox so you wont get exactly what you get on pc but you will get bug fixes
yes
No, Team Fortress 2 has no split-screen option.
The Orange Box games collection, which includes Half Life 2, Portal and of course Team Fortress 2
Not yet.
No, there are no cheat codes for TF2 on the Xbox 360. There are only glitches and exploits, but those get patched fairly quickly.